The area of research covered in this project is the cellular physiology of arthropod visual systems. Of particular interest are the visual processes which require integration such as sensitivities to wavelength and polarization. The methods of approach are electrophysiological, anatomical, and behavioral and experiments are conducted on both insect and crustacean species. Specific efforts include: 1) Electrophysiological unit recordings, intracellular and extracellular, from photoreceptors and visual interneurons yielding measures of spectral sensitivity, polarization sensitivity, and receptive fields. 2) Iontophoretic injection of fluorescent dyes yielding anatomical identification of physiological cell types and their projections in the visual system. 3) Behavioral experiments testing the involvement of the visual system in entrainment of circadian activity patterns to photic stimuli and conditioning experiments testing the ability of the visual system to discriminate wavelength.